Does epoxy resin make the board lighter. Can you just use normal cloth and a clark blank or do you have to have a special kind of blank.
You can use a Clark blank (polyurethane foam) with epoxy. And, also use normal glass such as E and S cloth.
Maybe one of the pros can jump on the weight topic - I believe epoxy lets you get away with using less materials - that is combinations of resin, cloth, and blank choices.
It takes less Resin Research epoxy to wet out the fiberglass cloth and the resin itself is slightly lighter in weight. So yes you’re board will be lighter using epoxy instead of Poly with all other things being equal.